Hip arthritis is a degenerative condition that affects the hip joint, and often leads to a significant impairment in the quality of life. The ability to walk, work and live pain free can be adversely affected. Approximately 43 million Americans suffer from arthritis and many of them are affected in the hip joint. In general, the treatment of hip arthritis involves activity modification, exercises, and treatment with anti-inflammatory medications. The use of assist devices such as canes, crutches or walkers can also be helpful. Occasionally surgical reconstruction such as total hip replacement is necessary.

What is the hip joint and what does it do?

The hip joint is a ball and socket joint. The acetabulum, or socket, is formed by three areas of the pelvic structure: the ilium, the ischium, and the pubis. The femoral head is the "ball", which is located on the upper end of the femur. There is a high degree of fit and stability within this ball and socket joint. It is stabilized by strong ligaments in the front of the hip which prevent dislocation. Both the femoral head and the acetabulum are covered with a layer of cartilage which provides shock absorption and load distribution within the hip. This cartilage is also a source of nutrition for the joint. Numerous muscles play an important role in the stability of the hip, one of which is the gluteus medius. This is a deep muscle within the buttock, and its proper function is important in normal walking.

Function
Approximately 3 times the body weight is distributed through the hip with routine activities due to the muscle pull and joint forces that occur. Any degenerative condition within the hip will alter biomechanical relationships and can cause limping, leg length inequality and disability. The stability of the hip joint is maintained by the precise fit of the femoral head within the acetabulum. The hip allows rotation in many planes. These include: flexion/extension (used most commonly in sitting), internal and external rotation (used with twisting activities), and abduction and adduction (inward and outward motion of the hip in a scissoring action).

What is hip arthritis?

Hip arthritis is any condition that leads to degeneration of the hip joint and its cartilage surfaces. Some of these conditions are osteoarthritis, rheumatoid arthritis, avascular necrosis and congenital dysplasia (dislocation) of the hip. Fractures and other injuries to the hip joint can also lead to hip degeneration.

Osteoarthritis is a degenerative condition that may affect many joints throughout the body. It causes changes in the mechanical structure of the cartilage, which lead to its breakdown. Over time complete loss of the articular cartilage can occur. Changes in the underlying bone and loss of cartilage can result in joint space narrowing, peripheral osteophytes (bone spurs), loss of motion, pain and disability.

Rheumatoid arthritis is an inflammatory condition that affects the lining of all joints in the body. It causes an inflammatory response in the joint lining which destroys the articular cartilage and surrounding tissues.

Osteonecrosis or avascular necrosis is a condition in which the bone within the femoral head dies. This eventually leads to the collapse of large segments of the bone supporting the cartilage of the hip joint. It ultimately causes the destruction of the hip. The main causes of osteonecrosis include:

injury such as femoral head fracture or hip dislocation.
high dose corticosteroid employed in the treatment of lupus , asthma, and spinal cord injury.
heavy alcohol abuse.

The final common pathway of hip arthritis is loss of the fit between the femoral head and the acetabulum. This results in thinning or complete loss of the cartilage, limitation of joint motion, shortening of the leg and continual pain and disability.